Learned something new!

[jnecr]

I always knew that the fuel "lines" in the new PD engines were actually just passages in the head. But.. I never really thought about how the fuel entered the injector.

Here's a few pics:
Seemingly the only hole in the injector:
http://www.ncdubs.com/photopost/data/503/injectorlarge.jpg

A little closer, as if you can't see it well enough:
http://www.ncdubs.com/photopost/data/503/injectorzoom.jpg

So that is the return fuel orifice.

Here are the entry orifices:
http://www.ncdubs.com/photopost/data/503/injectorlarge2.jpg

http://www.ncdubs.com/photopost/data/503/injectorzoom1.jpg

Pretty crazy, each hole is apparently 25microns wide...

[Shiftlink]

Yeah, that's pretty cool. They use a very similar system on some of the newer heavy diesels, Catepillar and Cummins. I was checking them out up at Guilford Tech, they have a tester that they can bolt them into and then pull a handle that compresses the fuel, and psssshh the fuel sprays out, you can check the pressure that it opens with and the spray pattern, very cool, looks like a big ass cloud of fuel. Those were opening at around 2000psi.

[jnecr]

yeah, Bosch started the unit injector with the big diesels and it's gone on to passenger car diesels now. The small injectors (like mine) open at pressures around 28,000 psi.